The device described in this proposal addresses the need identified for high-density percutaneous feedthroughs and implantable electrical connectors for neural prosthesis. The goal is to develop a chronic system for the transcranial delivery of signals from high density, multichannel electrode arrays implanted in mammalian sensory and motor cortexes. In Phase I, a hermetic multi-layer ceramic package, capable of being mounted on top of the skull to house VLSI circuitry, was developed and demonstrated. Phase II will make minor design changes to the package and convert the metal flanges and braze to biocompatible materials such as titanium and gold braze. A polymide and/or Parylene microribbon cable (25 mum spacing, 15 mum thick) and a method of bonding it to the back of the microelectrode array and to the base of the ceramic package will be developed. A VLSI chip will be designed and manufactured that has up to 100 channels of pre-amplification, a high speed multiplexer, and an A/D converter. The final assembly of array, microribbon cable, ceramic package and VLSI chip will be tested in vitro and in vivo (cat auditory cortex for about three months). PROPOSED COMMERCIAL APPLICATION: The chronic transcranial electrical connector will be marketed to neuroscience researchers to enable them to use multielectrode arrays in chronic investigators of the parallel processing of the mammalian brain. The ceramic will also provide them with a platform on which to develop circuitry for human neuroprosthetics.